William James discusses conversion experiences in his “Varieties of Religious Experience” Lectures IX and X.  Many people might assume that a conversion experience must take somebody from one faith or no faith to a new faith, such as happened to St Paul on the road to Damascus according to Acts Chapter 9 and Chapter 22.   Yet, James defines conversion in broader terms, writing… “To be converted, to be regenerated, to receive grace, to experience religion, to gain an assurance, are so many phrases which denote the process, gradual or sudden, by which a self – hitherto divided, and consciously wrong inferior and unhappy – becomes unified and consciously right superior and happy, in consequence of its firmer hold upon religious realities…” p.186 In this way, a conversion experience is one in which a person gains a new and unified purpose in faith and so includes the famous conversion of St Augustine, described in his Confessions, in which he “converted” from having a purely academic interest in Christianity to having an all-consuming faith after hearing a voice commanding “tole, lege.”  James argues that conversion experiences, like mystical experiences, have four common features, including

1. “The loss of all the worry, the sense that all is ultimately well with one, the peace, the harmony, the willingness to be…
2. the sense of perceiving truths not known before….
3. the objective change which the world often appears to undergo. “An appearance of newness beautifies every object,”
4. the ecstasy of happiness produced.” James p245-249

As James rightly argues, while not all claimed-conversion experiences are credible, there are some which share all four of these common features, which are amongst the most credible and research-worthy religious experiences, and which serve to demonstrate the inadequacy of narrow medical materialism and provide a pointer to the existence of God. Conversion experiences provide a sound basis for belief in God for those who have them… in practice they cannot not believe after having had one… but someone else’s conversion experience is not a sufficient basis for someone else to believe in God. 

Firstly, James considers the medical explanation of conversion experiences offered by his contemporary Professor Starbuck and rightly rejects it as a complete explanation for this type of experience, while acknowledging that some claimed conversions might be accounted for in this way.  Starbuck attempted to explain away conversion experiences as a natural psychological phenomenon of later adolescence, being accompanied by “a sense of incompleteness and imperfection; brooding, depression, morbid introspection, and sense of sin; anxiety about the hereafter; distress over doubts, and the like.” p.195 and resulting in:  “a happy relief and objectivity, as the confidence in self gets greater through the adjustment of the faculties to the wider outlook” p.195  James rightly accepts that many adolescents do have such experiences, but notes that these might be ”imitative” and that there are sporadic adult examples of conversion which might be the “originals” and which are worthy of further study.  An example of such an “original” might be the conversion of St Augustine.  While Augustine was certainly filled with a sense of incompleteness and what he called “soul sickness” prior to the conversion, and while his conversion did lead to a sort of resolution of these feelings, St Augustine was 30 and so no adolescent at the time of his conversion. Further, the fruits of Augustine’s conversion demonstrate that it was not an adolescent phase or a flash-in-the-pan… it changed Christianity and so changed the world!  St Augustine was never affected by any doubt or backsliding, as one might expect if the experience had been the result of an adolescent psychological crisis. In this way, James was correct to reject Starbuck’s adolescent crisis explanation as a full explanation for conversion experiences and correct to consider some “original” examples of conversion experience – such as that of St Augustine – as worthy of further study and as a pointer to the existence of God if not any kind of proof.  It follows that conversion experiences point towards the existence of God but fall short of being a good basis for believing in God for those who have not had one.

Secondly, James considers the medical explanation of conversion experiences offered by his contemporary Professor Leuba and rightly rejects it as a complete explanation for this type of experience, while acknowledging that some claimed conversions might be accounted for in this way.  For Leuba, conversion experiences emerge out of a deep sense of moral imperfection and sin.  James acknowledges that some experiences do follow this pattern, and this is fair.  Perhaps St Paul’s conversion is the most obvious example to support James’ point.  Might St Paul have been brooding subconsciously on his own role in persecuting Christians, even holding the coats during the stoning of St Stephen?  Could this sense of moral imperfection – bearing in mind Paul’s Pharisaic training and beliefs – have prompted him to have a moral crisis to facilitate regeneration, doing a 180 degree turn in terms of his behaviour to cope with past guilt?  In this way we might compare St Paul with the gangsters who become saints on death row; facing judgement they can only cope by being habitually reborn and utterly changing as a person.  Yet again James argues that Leuba is seeking to explain away all conversion experiences based on a few.  He wrote “in spite of the importance of this type of regeneration, with little or no intellectual readjustment, this writer [Leuba] surely makes it too exclusive” p. 200 This is convincing because no two conversion experiences and no two individuals are alike. As James wrote, “there are distinct elements in conversion, and their relations to individual lives deserve to be discriminated” p.200   Further, even if Leuba was right and the conversion did result from a moral crisis, there is no way to know that the conversion is not God’s answer to the crisis.  God could be working through the brain’s capacities to effect change within the subject, just as God might work through the sun at Fatima or through the waters of the Red Sea when it parted.  How else, after all, could God act on his creation than through his creation?  Nevertheless, James was right to argue that it would be wrong for a third party to believe in God on the strength of somebody else’s claimed conversion experience – however credible it might seem – because (as Hume pointed out in his essay “On Miracles”) it is always possible that that person has been lying, is deluded or ill.  While Dean Inge and William Alston would disagree, claiming that we should believe people unless we have a good reason not to, as Carl Sagan pointed out “exceptional claims demand exceptional evidence” and the fact that the testimony relates to something we cannot verify and can explain in ways that we can, however unlikely, means that we cannot see such testimony as sufficient basis for belief in God.  However, James was also right to point out that a conversion experience is sufficient basis for belief for the person who has been converted.   A characteristic of the conversion experience is that the world seems to change objectively, so that it becomes impossible for the subject not to believe what they have experienced.  As James wrote: “A small man’s salvation will always be a great salvation and the greatest of all facts for him” p.235 and “the sense of renovation, safety, cleanness, rightness, can be so marvellous and jubilant as well to warrant one’s belief in a radically new substantial nature…” p224 It follows that a conversion experience is a good basis for belief in God for those people who have had one.

Further, “original” examples of conversion experience conform to the marks of genuine religious experience proposed by scholars including Otto, Stace and Tillich. For Otto, as he explains in “The idea of the Holy” every genuine experience is characterised by “mysterium tremendum et fascinans.” He described how the experience should include a sense of “piercing acuteness… accompanied by the most uncompromising judgment of self-depreciation, a judgment passed, not upon his character because of individual ‘profane’ actions but upon his very existence as creature before that which is supreme above all creatures.”  As James noted, this sense of utter inadequacy, awe and dread is a hallmark of the first stage of a conversion experience, as a person confronts their soul-sickness and inadequacy in the face of God. For Stace, a genuine experience must be of a non-sensuous unity in all things, similar to what Tillich referred to as “the ground of our being”.  A genuine experience is not a sensory experience of something external that we can sense through eyes or ears in any literal way, but something inward.  In this way, conversion experiences have more claim on being genuine experiences than corporate experiences – which are often of something seen, heard or felt – or of many mystical experiences, which might take the form of visions or voices.  St Augustine’s conversion was not the voice saying “tole, lege”… that might well have been the child in the garden… it was only prompted by the voice, the experience was  profoundly inward and non-sensuous.  In this way, conversion experiences have a good claim to being credible religious experiences by the definitions of scholars other than James.  Also, in their ineffable and non-sensuous nature, conversion experiences are not sectarian and are not undermined by the classic criticism of Hume that they exist in all religious traditions and therefore somehow cancel each other out.  On the contrary, conversion experiences point to the unity that underpins all religious traditions, a God whose nature and attributes are consistent with the other arguments for God’s existence and not, as is the case for other forms of religious experience, a God whose nature and attributes seem at odds with reason. 

In conclusion, as James rightly argued, conversion experiences provide sufficient basis for belief in God for those who have had one.  Indeed, it is impossible for the recipient of a genuine conversion experience not to believe.  However, conversion experiences do not provide sufficient basis in themselves for people in general, who have not had a conversion experience themselves, to believe in God.  It is always possible that individual experiences are, as Starbuck and Leuba suggested, the psychological result of an adolescent or a moral crisis.  It is always possible, as Hume suggested, that the subject is lying, deluded or ill.  Nevertheless, it is equally possible that God works through the brain, responding to adolescent or moral crises in a way whose power and goodness is demonstrated by its effects in the life of the subject and in the lives of those they touch.  Rather than basing belief on a single piece of evidence such as conversion experience, it makes more sense to base it on a cumulative case as Richard Swinburne outlines in his “The Existence of God” (2004)  Once the “prior probability” of God’s existence has been established then it becomes reasonable both to believe what we ourselves experience (Principle of Credulity) and to believe what others tell us (Principle of Testimony) so that we can amass a bank of examples of credible religious experiences, including “original” conversion experiences like those of St Augustine and St Paul, which may tip the balance in favour of believing in God, making God’s existence more probable than His non-existence.  While skeptics like Flew and Dawkins will surely disagree, arguing that “ten leaky buckets are no better than one”, in practice it is just as reasonable to believe in God on the strength of a strong abductive case as it is to convict somebody in a court of law on the strength of a strong abductive case.